To deal with various forums and novel techniques in relation to 4th mobile communication system, 3GPP stipulating technical standards of 3rd mobile communication system started to study an LTE/SAE (Long Term Evolution/System Architecture Evolution) technique as part of efforts to optimize and improve the performance of 3GPP techniques in late 2004. The SAE, which has proceeded based on 3GPP SA WG2, relates to a network technology aiming at determining a network structure by interworking with an LTE operation of 3GPP TSG RAN and supporting mobility between heterogeneous networks. The SAE, one of the key standardization issues of 3GPP, is to advancing a 3GPP system to a system supporting various radio access techniques based on an IP, and working for an optimized packet-based system which may be able to minimize a transmission delay with improved data transmission capabilities.
Technical terms used in the present disclosure will now be described.                An MTC function is a function of supporting communication between MTC devices or between an MTC device and an MTC server, which performs communication without an intervention of a human being, unlike the existing person-to-person connection. For example, an MTC application may include communication between an automatic vending machine and a server, a POS (Point of Service) device and a server, an electricity or water meter and a server. Here, the corresponding device is called an MTC device. The MTC is also called machine-to-machine communication.        TA (Tracking Area) refers to an area in which an E-UTRAN provides a service, including one or a plurality of E-UTRAN cells. An RA (Routing area) refers to an area in which a GERAN/UTRAN provides a service, including one or a plurality of GERAN/UTRAN cells.        —TAI (Tracking Area Identity) list refers to a list of TA identities identifying tracking areas a user equipment (UE) may enter without having to perform a TA updating procedure. The TAIs in the TAI list assigned by an MME (Mobility Management Entity) to a UE pertain to the same MME area. A detailed description of the TAI list will quote the matters stated in the standard document 3GPP TS 24.301 v9.1.0.        MME area: An MME area is the part of the network served by an MME. The MME area includes one or a plurality of TAs. All the cells served by an eNodeB are included in an MME area. A detailed description of the MME area will quote the matters stated in the standard document 3GPP TS 23.002 v9.2.0.        —UMTS: It stands for Universal Mobile Telecommunication System, which means a 3G network.        —EPS: It stands for Evolved Packet System, a core network supporting an LTE access network. Also, the EPS has evolved from UMTS.        —NodeB: It is a base station of a UMTS network, which is installed in an outdoor area and has coverage of a macro cell size.        —eNodeB: It is a base station of an EPS network, which is installed in an outdoor area and has coverage of a macro cell size.        —UE: It stands for User Equipment, which means a UE device.        —IMSI: It stands for International Mobile Subscriber Identity, which is a user's unique identifier assigned solely internationally in a mobile communication network.        —SIM card: It stands for Subscriber Identity Module, which is used to have the same meaning as a SIM card.        —MTC: It stands for Machine Type Communication, which refers to communication performed between machines without a human being's intervention.        —MTC device: It refers to a UE (or UE) performing a particular purpose having a communication function through a core network. The UE may be, for example, a vending machine, a meter or a gauge, or the like.        —MTC server: It refers to a server which manages an MTC device and transmits and receives data in a network.        —MTC application: It is an actual application using an MTC device and an MTC server, including, for example, inspection of a meter, tracking a supply movement.        —MTC feature: functions or features of a network supporting an MTC application, namely, some features, are required according to the purpose of respective applications. The MTC features may include, for example, MTC monitoring (e.g., required for a remote inspection of a meter in preparation for a loss of equipment), low mobility (e.g., in case of a vending machine, it scarcely moves.        —RAN: It stands for Radio Access Network, which is a general term for 3GPP radio access such as RNC, NodeB, or eNodeB.        —HLR (Home Location Register)/HSS (Home Subscriber Server): It is a database (DB) representing subscriber information within a 3GPP network.        —RANAP: It stands for Radio Access Network Application Part, which refers to an interface between RAN and network nodes (MME/SGSN/MSC) which are in charge of handling a core network.        —ICS (IMS Centralized Services): It stably provides a consistent service of IMS regardless of an access network to which a UE is attached (namely, although the UE is attached to a CS domain as well as to an IP-CAN). A detailed description of the ICS will quote the matters stated in the standard document 3GPP TS 23.292 v9.4.0.        —IMS (IP Multimedia Subsystem): It refers to a system providing a multimedia service on the basis of an IP network.        —Attach: It refers to a connection of a UE to a network node, including an attach generated in the occurrence of handover in a broad sense.        —Point of attachment: It refers to an access point of a UE.        
The present invention will now be explained with reference to the foregoing technical terms.
FIG. 1 is a conceptual view of a 3GPP service model for supporting MTC.
GSM/UMTS/EPS of 3GPP standard defines communication through a PS network, but in the present invention, a method applicable even to a CS network will be described. A definition of a network architecture in a current technical standard has been proposed to use an existing bearer of 3GPP. Meanwhile, a method of using an SMS (Short Message Service) for exchanging data between an MTC device and an MTC server has been proposed as one of alternative solutions. The use of SMS has been proposed in consideration of the fact that a small amount of digital data such as metering information, product information, or the like, is handled in UEs of the MTC application, by which the existing SMS method and an SMS method on the basis of an IMS can be supported In FIG. 1, MTCsms is a data exchange interface through the existing SMS method, and MTCi is a data exchange interface through the IMS-based SMS method. In addition, there are methods for regulating a paging range for an MTC application with a little mobility.
The 3GPP system such as the conventional GSM/UMTS/EPS is defined for communication between end-users, namely, between human beings. However, the conventional mobile communication system is not effective for communication between an MTC device and an MTC server, and also not an optimized communication solution. Thus, recently, 3GPP has set to work to define functions and mechanisms for exchanging data between the MTC device and the MTC server, but detailed, substantial methods still remain insufficient. Also, in terms of numerous MTS applications, the MTC device is independently installed and operated without a human being's operation. In this state, the MTC device may be lost, broken down, or malfunction, so in order to automatically manage the MTC device, there is a need to check (or monitor) whether or not the MTC device is in an online or offline. Also, in order to check whether or not the MTC device is in online or offline, a technical necessity to be supported by the function of an existing network system, e.g., a 3GPP core network, rather than establishing a network and a system to a separate management is required. Namely, the advantages of maximizing utilization and efficiency of communication of the existing network and channel resources can be obtained by using the existing network infrastructure.